Patient Explainers
Plain-language explanations of common tests and scores.
ClinCalc Pro is built for clinicians, but these plain-language pages explain common clinical tests and scores for patients and anyone who wants to understand a number their doctor has mentioned. They are general information, not personal medical advice.
- What is eGFR?eGFR is a blood test that estimates how well your kidneys filter your blood. Learn what your eGFR number means and what the CKD stages are, in plain English.
- What is a CHA₂DS₂-VASc score?The CHA₂DS₂-VASc score estimates the risk of stroke in people with atrial fibrillation (an irregular heartbeat), and helps doctors decide about blood-thinning medicine.
- What is BMI?BMI (body mass index) is a number from your height and weight used as a rough guide to whether you are a healthy weight. Learn what the categories mean and their limits.
- What is HbA1c?HbA1c is a blood test that shows your average blood sugar over the past two to three months. Learn what the numbers mean for diabetes, in plain English.
- What is the HEART score?The HEART score helps doctors in A&E judge how likely chest pain is to be due to a heart problem. Learn what it includes and what the result means, in plain English.
- What is a troponin test?Troponin is a blood test that helps doctors find out if heart muscle has been damaged, for example in a heart attack. Learn what a raised troponin means, in plain English.
- What do blood pressure numbers mean?Blood pressure is given as two numbers — systolic over diastolic. Learn what they mean, what counts as high, and why home and clinic readings can differ, in plain English.
- What is a cholesterol test?A cholesterol (lipid) test measures fats in your blood — total, LDL, HDL and triglycerides. Learn what the numbers mean for your heart and stroke risk, in plain English.
- What is INR?INR measures how long your blood takes to clot and is used to monitor warfarin. Learn what your target range means and what can change your INR, in plain English.
- What is a CRP test?CRP (C-reactive protein) is a blood test that rises with inflammation and infection. Learn what a high CRP means and why it is not specific, in plain English.
- What is a thyroid function test?Thyroid function tests (TSH, T4) check whether your thyroid gland is underactive or overactive. Learn what high and low TSH mean, in plain English.
- What is a ferritin test?Ferritin is a blood test of your body's iron stores. Learn what low and high ferritin mean — and why inflammation can affect it — in plain English.
- What does a potassium blood test mean?Potassium is a salt vital for your heart and muscles. Learn what high (hyperkalaemia) and low (hypokalaemia) potassium mean and why they can be serious, in plain English.
- What is a D-dimer test?A D-dimer blood test helps rule out blood clots (DVT and PE) in people at low risk. Learn what a positive result does and doesn't mean, in plain English.
- What is a PSA test?PSA is a blood test linked to the prostate. Learn what a raised PSA can and can't tell you about prostate cancer, and why it is a shared decision, in plain English.
- What is a liver function test?Liver function tests (LFTs) — ALT, AST, ALP, bilirubin and albumin — check the health of your liver. Learn what raised results can mean, in plain English.
- What is a full blood count?A full blood count (FBC) measures your red cells, white cells and platelets. Learn what anaemia, a high white count and low platelets can mean, in plain English.
- What is sepsis?Sepsis is the body's extreme, life-threatening response to an infection. Learn the warning signs and why it is a medical emergency, in plain English.
- What is atrial fibrillation?Atrial fibrillation (AF) is a common irregular heart rhythm that raises the risk of stroke. Learn the symptoms and why blood thinners are often used, in plain English.
- What is a stroke?A stroke is a brain attack caused by a blocked or burst blood vessel. Learn the FAST warning signs and why it is a 999 emergency, in plain English.
- What is a heart attack?A heart attack happens when blood flow to the heart muscle is suddenly blocked. Learn the symptoms and why it is a 999 emergency, in plain English.
- What is a DVT?A DVT is a blood clot in a deep vein, usually in the leg. Learn the warning signs and why it needs urgent assessment, in plain English.